1. Field of Invention
The stabilization of paprika pigments upon exposure to air with certain digestible surface-active agents, and synergistic combinations of such stabilized pigments with natural antioxidants which further increase their stability.
2. Prior Art
Both ground paprika and its oleoresin are known to lose color rapidly upon exposure to air, due to oxidation of the pigments. Degradation is further accelerated upon exposure to heat and to light. Common antioxidants used in food, such as BHA, BHT, and TBHQ do not markedly inhibit this loss. Therefore, FDA has allowed the use of ethoxyquin as an antioxidant for use in ground paprika at a level of no more than 0.01%. It is the most effective stabilizer of paprika pigments known prior to this invention. Since it may have adverse toxicological properties, its use is not permitted as a direct additive to foods. It is not permitted as an additive to oleoresin paprika.
Encapsulation is another means of avoiding degradation of pigments, and this has been achieved by dissolving the pigment in a solvent, such as chloroform, admixing the solution at a high temperature with an encapsulating agent such as gelatin, and removing the solvent quickly In certain cases, bisulfite is used to prevent degradation, which is ojectionable as a stabilizer. Other systems use thiopropionates as antioxidants, and these are not permitted in foods Yet other systems depend on combinations of polyoxyethylene derivatives combined with BHA and BHT in the presence of substances which are cosolvents for the pigment and polyoxyethylene derivatives to make stable liquid combinations, from which the pigment will not crystallize. As shown in this specification, the presence of the polyoxyethylene derivative is highly destabilizing in the presence of oxygen, and the BHA/BHT antioxidants are ineffective.
The prior art shows condimental combinations of seasonings, including oleoresin of paprika, with various emulsifiers to achieve mutual compatibility as well as dispersibility in both oil and water. These systems did not have as their objective the stabilization of the pigments against oxidative or thermal stress and, indeed, suggested deleterious combinations of emulsifiers in terms of the objectives of this specification.
Accordingly, the present art is in great need of non-toxic, natural, effective systems which will preserve the color of paprika and its oleoresin when used in the manufacture of food which is subject to oxidative stress. This invention provides the first such system, which is much more effective than even an ethoxyquin system.
The heart of the invention lies in the totally unexpected effect which certain, but not all, emulsifiers have upon the stability of these pigments. As described hereinafter, these emulsifiers are not antioxidants, and indeed have a slight pro-oxidant effect when added to vegetable oils. Accordingly, the stabilizing effect must be attributed to an unknown mechanism, such as inhibition of electron transfer in the pigment when it quenches singlet oxygen, which then renders it more immune to the attack of oxygen. This, however, is only a hypothesis and not intended to be limiting.
Since the emulsifiers used in the stabilizing systems of this invention are readily digested by the enzymes secreted in the digestive tract, they will not block the electron transfer potential of the pigments after absorption by the body. Therefore, they will not impair their health benefits when a component of the diet. In this respect, no harmful additive, such as ethoxyquin, is introduced into the diet to preserve their effectiveness.
Various combinations of natural antioxidants with the paprika-emulsifier systems achieve stabilities which none of the substances can achieve alone, and indeed the stabilities achievable, for all practical purposes, are greater than a year, as opposed to a month using present art. This opens entirely new uses for paprika pigments.